Estrus Manipulation and Artificial Insemination Flashcards
What is estrus duration for cows
6-30hrs (average 18hrs)
Reasons for estrus manipulation
- Synchronize
- Initiate cylclicity in anestrous animals
- Out of season breeding in seasonal species
- Correct reproductive problem
What does PGF2alpha do
Induce luteolysis
When is corpus luteum responsive after PGF2alpha in cattle
6-7 days
What estrus manipulation drug promotes release of FSH and LH
GnRH analogs-gonadorelin, deslorelin
What drugs replicate LH surge
LH analogs- hCG
What drug is required for out of season breeding if only using drugs for manipulation
FSH analogs-eCG
What hormone is responsible for maintaining pregnancy and blocks LH surge
Progesterone
What species is cystorelin approved for
Dairy cattle only
What species is lutalyse approved for
Cattle, swine, mares
What species is estrumate approved for
Cattle
Use of ___in food animals is prohibited for estrus manipulation
Estradiol
What are the objectives of synch protocols in cattle
- Hormonally control the onset of new follicular wave
- Control the lifespan of both natural and induced CL’s
- Control time of ovulation for dominant follicle
What is the protocol for ovsynch
- Day zero: GnRH- ovulation of dominant follicle
- Day 7: PGF2alpha-luteolysis of CL
- Day 9: GnRH- ovulation of new dominant follicle
- 24-32hrs later TAI
Ovsynch doesn’t work well in heifers only __-__% synch rate, but in mature cows synch rate ___-___%
50-60%, 70-90%
What is the protocol for pre synch
Giving 2 injections of PGF2alpha prior to ovsynch to ensure majority of cows will be between 5-12 days of cycle
What is major shortcoming of ovsynch
Cattle between 14-15 days of their cycle will not respond to 1st GnRH injection (~10%)
Select synch works well with ___not ___
Mature beef cows, heifers
What is protocol for select synch
- Day zero: GnRH injection
- Day 7: PGF2alpha injection
- Day 6-13: watch for heat BID and AI 12hrs later
- Day 13: turn in clean up bulls
What is the least predictable step in embryo production and transfer
Super ovulation
Semen straws must be ___ and loaded into the AI gun
Thawed
Once semen straws are thawed cut the tip of the straw and load with Cotten end facing ___
Away from end of AI gun
